Son of Sara opens with a compelling premise. The opening hour moves through predictable genre beats, with Sara repeatedly ignoring increasingly alarming warning signs to a questionable extent. There’s no shortage of ambition behind Son of Sara, and Bone clearly has an eye for memorable horror imagery. The problem is that the film spends too long recycling familiar ideas before revealing the far stranger movie hiding underneath. Had it reached its wonderfully bonkers destination sooner – and invested more in developing its characters along the way – this could have been a genuinely memorable addition to the pregnancy horror subgenre.